Polyunsaturated fatty acids (PUFAs), including omega-3, omega-6 and omega-9 fatty acids, are vital to everyday life and function. For example, the beneficial effects of omega-3 fatty acids like all-cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) on lowering serum triglycerides are well established. All-cis-9,12,15-octadecatrienoic acid (ALA) is the precursor essential fatty acid of EPA and DHA. All-cis-5,8,11,14-eicosatetraenoic acid (AA) and its precursors all-cis-6,9,12-octadecatrienoic acid (GLA) and all-cis-9,12-octadecadienoic acid (LA) have been shown to be beneficial to infants.
Various of these compounds are also known for other cardioprotective benefits such as preventing cardiac arrhythmias, stabilizing atherosclerotic plaques, reducing platelet aggregation, and reducing blood pressure. See e.g., Dyrberg et al., In: Omega-3 Fatty Acids: Prevention and Treatment of Vascular Disease. Kristensen et al., eds., Bi & Gi Publ., Verona-Springer-Verlag, London, pp. 217-26, 1995; O'Keefe and Harris, Am J Cardiology 2000, 85:1239-41; Radack et al., “The effects of low doses of omega-3 fatty acid supplementation on blood pressure in hypertensive subjects: a randomized controlled trial.” Arch Intern Med 151:1173-80, 1991; Harris, “Extending the cardiovascular benefits of omega-3 fatty acids.” Curr Atheroscler Rep 7:375-80, 2005; Holub, “Clinical nutrition: 4 omega-3 fatty acids in cardiovascular care,” CMAJ 166(5):608-15, 2002. Indeed, the American Heart Association has also reported that omega-3 fatty acids can reduce cardiovascular and heart disease risk. Other benefits of PUFAs are those related to the prevention and/or treatment of inflammation and neurodegenerative diseases, and to improved cognitive development. See e.g., Sugano and Michihiro, “Balanced intake of polyunsaturated fatty acids for health benefits.” J Oleo Sci 50(5):305-11, 2001.
In addition to fish oil sources, PUFAs can be and are derived from microbial sources including, without limitation, Mortiarella alpina for ARA and various species of Thraustochytrids for DHA and EPA. Plants are now being modified genetically to include genes that produce various PUFAs in further efforts to reduce costs associated with commercial production of these oils.
Despite the strong evidence for the benefit of PUFAs in prevention of cardiovascular disease, the average daily consumption of these fatty acids by North Americans is estimated to be between 0.1 to 0.2 grams, compared to a suggested daily intake of 0.65 grams to confer benefit (Webb, “Alternative sources of omega-3 fatty acids.” Natural Foods Merchandiser 2005, XXVI (8):40-4). Since altering dietary patterns of populations is difficult the supplementation of diets with PUFAs is an important approach to addressing this problem. Unfortunately, many PUFAs are sensitive to oxidation and can have unpleasant organoleptic properties. Further, compliance with dietary supplement regimens requires discipline, which is often wanting. In light of the health benefits of PUFAs it is desirable to find new ways to deliver these and other beneficial materials to a subject.
Delivery of PUFAs by formulating them into comestible compositions would be a desirable method from a consumer acceptability and compliance standpoint. However, the hydrophobicity and oxidative stability characteristics associated with many PUFAs creates significant challenges for incorporating them into comestible compositions. One approach involves the use of emulsions. Emulsions have been used as delivery vehicle for various substances. For example, emulsions have been used in the cosmetic, detergent, personal care, agricultural, and oil exploring industry. However, most emulsions are not water dilutable; that is, the emulsion becomes cloudy or milky white upon dilution by water. As such, there has been a good deal of interest in obtaining an emulsion that remains clear upon dilution and is stable over a long period of time. For commercial purposes, the creation of emulsions that remain clear upon dilution and are stable over a long period of time has been a goal. It is also of importance that the emulsion has a high loading factor, for more efficient delivery, and is inexpensive enough to be cost effective in cost sensitive beverages. The process for preparing such an emulsion must also be commercially cost effective. An emulsion with these properties can be incorporated in to waters and other clear or near clears beverages without affecting the beverage's underlying appearance and without significantly increasing the cost of the beverage to the consumer. This goal has not yet been satisfactorily attained with PUFAs, esters, and glycerides thereof.
U.S. Pat. No. 5,798,333 discloses a method of making a water dilutable, clear cyclosporine-in-water emulsion using tocophersolan (Vitamin E TPGS) as the emulsifier. This patent discloses the use of excess (7.5 times) emulsifier to dissolve cyclosporine. Cyclosporine has a low molecular weight and better solubility than various long chain PUFAs. The finished product is a semi-solid non-flowing gel contained in two-piece gelatine capsule.
International publication WO2009/117152 discloses a water dilutable, clear non-polar nanoemulsion containing Vitamin E TPGS, omega-3 triacylglycerol fish oil, and water. The ratio of emulsifier to fish oil is from 1.6:1 (w/w) to 6:1 (w/w). Also, additional components including benzyl alcohol, propylene glycol, glycerol, phospholipids, and a gum based emulsion stabilizers are used.
In another example, from U.S. Pat. No. 5,753,241, a very high pressure homogenization step at 108 Pa was used to make the emulsion. However, such pressure is generally beyond the normal pressure range used in food applications, which is normally from 1500 psi to 6000 psi.
In light of the above, what are needed in the art are emulsions of PUFAs and other beneficial materials and methods for their preparation where the emulsion is not discernable in the liquid in which it is incorporated, has a high loading factor, has favourable organoleptic properties, and is cost effective. The compositions and methods disclosed herein meet these and other needs.